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Handbook of Size Exclusion Chromatography and Related ...

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Figure 5 Pore size distributions <strong>of</strong> HPLC silicas. Internal surface area vs. pore diameter<br />

for four commercial 5-mm silicas were determined by mercury intrusion using<br />

Micromeritics Autopore II 9200 at pressures up to 60,000 psi (400 MPa). Packing<br />

materials, LiChrospher Si-100 (Lot 602F659316), Spherisorb S5W (Lot F5259), Supelcosil<br />

LC-Si (Lot 180-86), <strong>and</strong> Zorbax BP-Sil (Lot 20357-58).<br />

commercial 5-mm silicas with pore sizes ranging from 60 to 120 A ˚ as determined<br />

by mercury porosimetry (R. Eksteen, unpublished results, 1986). This technique<br />

can measure pore diameters down to 30 A ˚ , which is the upper limit <strong>of</strong> the size<br />

range for micropores. Note that the data in Fig. 5 are biased toward the smallest<br />

pore sizes, which by virtue <strong>of</strong> their number can contribute significantly to the total<br />

surface area while representing a relatively smaller fraction <strong>of</strong> the total pore<br />

© 2004 by Marcel Dekker, Inc.

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